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View Full Version : The UPS & Downs of Slowly Staying on Top of it All


UNCTUOUS
10th Feb 2004, 01:21
What a conundrum. Should've believed the higher speed. It would have got him home that much faster.

This is much the same as the water trapped in the static lines turning to ice in the climb scenario - with IAS reducing to zero over a few thou feet - though with no rate of climb and a stuck altimeter, who's to know that? (it's a little more disconcerting in this incident though - as it doesn’t melt later as you descend below FZLVL).

Those darn maintainers keep figuring out new ways of trying to kill people.

From the Irish Examiner

09/02/04
Jet crew averted Dublin air disaster
By Caroline O'Doherty

THE crew of a jumbo jet averted disaster in the skies over Dublin when they managed to land the aircraft without knowing how fast it was going or how high it was flying.

The Boeing 747 cargo plane operated by United Parcel Service caused a full-scale emergency at Dublin Airport when key instruments failed after a pre-flight checking error by maintenance staff.

At one point as the flight commander turned the stricken plane for home, he had three different speed readings ranging from 170 knots to 300 knots and did not know which, if any, was correct.

He also, according to the resulting inquiry by the Department of Transport's Air Accident Investigation Unit, "had no idea of his true altitude except that he was staying on top of the clouds".

To compound the 39-minute crisis, the crew's preferred option of re-routing to Shannon where there was a longer runway was ruled out because of bad weather.

Investigators said the performance of the commander and his seven crew members was excellent and was the key factor in bringing the plane home safely in what they said was a "potentially disastrous situation".

They said the crew and aeroplane were also saved by the fact that they were on a test flight which was routine following maintenance and such flights were only conducted during daylight.

The incident happened in May 2000 but the report has only just been published. The AAIU said its investigation was hampered by confusion among staff about a parallel investigation by the Irish Aviation Authority.

The AAIU's function is to investigate incidents with a view to making safety recommendations without apportioning blame while the IAA has the power to prosecute and sanction personnel and formally cautions them prior to beginning an inquiry.

"It is therefore possible that the staff experience of being formally cautioned during the course of an IAA investigation may have had a detrimental effect on the willingness of staff to assist the AAIU investigation of this occurrence," the report states.

Investigators found that staff with Team FLS, an aircraft maintenance contractor at Dublin Airport, had left open the drainage caps on air pressure ports on the aeroplane, believing that the next shift taking over would complete the maintenance programme and pre-flight check. The next shift in thought the job was complete.

The ports measure air pressure while the plane is stationery and moving, the difference between the two giving the airspeed. Left open, the static drainage ports gave an incorrect reading resulting in a falsely low airspeed.

Irish AAIB Report here (http://www.aaiu.ie/AAIUviewitem.asp?id=4703&lang=ENG&loc=1652)

radeng
10th Feb 2004, 23:42
Shows why pilots ought to be paid a lot for their abilities! As a non pilot, I'd have come back from that trip with brown underwear.

Field In Sight
11th Feb 2004, 01:18
Sound's like he should of had a handheld GPS and a windcheck from ATC. :O

FIS

Smedley
11th Feb 2004, 03:00
I wonder if the Angle of Attack instrument was functioning?

It operates independently of the Pitot Static system.

Major Attack
11th Feb 2004, 05:16
Smedley.

It didn't have any AoA instrument, that was a suggested additional recommendation from UPS (if I remember correctly).
Most modern civilian jets don't have any AoA indexer or instruments, but military jets usually have one.

Mj Attack

dallas dude
11th Feb 2004, 07:48
radeng

In case you didn't know the pilot's trousers were indeed very brown!

Cheers,dd

(for those who don't know UPS pilots wear a fetching shade of brown)

Shore Guy
11th Feb 2004, 14:31
UPS 747's have a rudimentary AOA device......the stick shaker(s) driven by AOA information. There is no dedicated AOA display.

I have not studied the report, but I don't believe they got a shaker during this event.

With all the distractions mentioned in the report (air data, vibrations, etc.), it appears the crew did a good job. Aircraft have crashed with lesser anomalies.